Sampras says 'beast' Nadal could become greatest ever

The 14-time grand slam tennis champion Pete Sampras has described Rafael Nadal as a beast who is capable of overtaking Roger Federer as the all-time grand slam king.

The 24-year-old Spaniard claimed his ninth grand slam crown by winning the US Open earlier this month and became the seventh man to complete a career grand slam in the process.

Federer holds the record for most major titles with 16, having eclipsed the previous mark of 14 set by Sampras.

The American says the only question is physically how much Nadal's body can handle the pounding with how hard he works for every point, noting his relentless style of play.

Sampras says Nadal has no need to pad his resume to cement his place among the sport's all-time greats, as he's won all the majors and the Olympics and he's dominated his main rival Federer, referring to the Spaniard's 14-7 head-to-head edge over the Swiss master.

He says considering what he's achieved at such a young age Nadal has to be one of the three or four greatest tennis players of all time.